Soil pH in Sumter, SC: Lime or Sulfur?

Typical topsoil pH in Sumter, SC

Typical topsoil in Sumter, SC is pH 5.21, too acidic for vegetable garden. Expect roughly 9.1 lb of lime per 100 sq ft, but only after a soil test confirms it.

What Sumter needs, by plant

• Already in range: potatoes, blueberries, azaleas and rhododendrons, blue hydrangeas.
• Lime: lawn (cool-season grass) 9.1 lb/100 sq ft over 2 applications; vegetable garden 9.1 lb/100 sq ft over 2 applications; tomatoes 9.1 lb/100 sq ft over 2 applications; strawberries 5.6 lb/100 sq ft over 2 applications; roses 9.1 lb/100 sq ft over 2 applications; pink hydrangeas 7 lb/100 sq ft over 2 applications.

What to do next

If your test confirms pH near 5.21, spread about 91 lb of ground limestone per 1,000 sq ft of vegetable bed in 2 doses, ideally in fall.

How mixed the soil is

Of the 418,597 surveyed acres in Sumter, SC, 69% are strongly acidic (below 5.5), 31% are moderately acidic (5.5-6.5). Mapped soils run from pH 4 to 6.4, a spread of 2.4 units across 211 soil components. 69% of the land falls in one class, so the county figure is a fair first guess for most yards here.

Clay, organic matter and rates

Topsoil here averages 14.9% clay and 4.64% organic matter, which this site treats as loam. Moving it one pH unit takes about 7 lb of lime or 2.3 lb of sulfur per 100 sq ft. None of the mapped components carry free carbonate.

Sumter against the rest of South Carolina

pH 5.21 is 0.09 below the South Carolina median of 5.3. 17 of 46 South Carolina counties have more acidic topsoil. Nationally it is more acidic than the US county median of 6.05.

Closest in pH within the state: Berkeley (5.18), Dorchester (5.19), Allendale (5.2), Calhoun (5.21), Barnwell (5.23), Lee (5.26), Georgetown (5.27), Chesterfield (5.28).

The range in South Carolina runs from Charleston at 4.8 to Beaufort at 5.92; Sumter sits 37% of the way up.